This is not a tutorial on how to use Cloudflare Workers or any of its features
At embed.rauf.wtf I allow users to pass in data and get a web embed which uses plain HTML and meta tags.
Dynamically set meta tags sound difficult at first using only plain HTML without a template language/view engine. However, with Cloudflare Workers it is 100% possible and fairly easy to do.
"Cloudflare Workers is a serverless application platform running on Cloudflare’s global cloud network in over 200 cities around the world, offering both free and paid plans." (https://developers.cloudflare.com/workers/get-started/guide)
Workers provides a HTMLRewriter which allows you to pass in a HTML request and modify it.
Content for the meta tags gets passed in through Query Params on the request url and I use the HTMLRewriter to select all the meta tag elements and add the content using a custom MetaHandler class.
class MetaHandler {
element(element) {
// Figure out which element it is
// Find the corresponding query param
// set the element's content: element.setAttribute('content', param data)
}
}
return new HTMLRewriter().on("head > meta", new MetaHandler()).transform(req);
In return it provides back the HTML but with the meta tag content modified to use the content from the request url which then gets send as the response body.